This invention relates to a camera capable of correcting a shake image blurring which can provide a distinct picture by correcting a shake of a light image projected on an exposure plane due to a camera shake.
A variety of shake-correctable cameras have been proposed. They are generally constructed such that a taking lens having a changeable optical axis and a sensor for detecting a shake direction and a shake amount of a light image of an object (hereinafter, referred as to "object light image") on an exposure plane (hereinafter, referred as to "shake information") caused by a camera shake are provided and the optical axis of the taking lens is changed based on the shake information detected by the sensor to cancel the shake of the light image on the exposure plane.
Specifically, a shake amount is predicted based on a rate of change of a shake amount detected by the sensor in a specified cycle, and the optical axis of the taking lens is changed in a specified cycle to cancel the predicted shake amount.
According to such a shake correction method, it is very difficult to predict a shake amount when there is a discontinuous and sudden shake. The shake correction using a shake amount before occurrence of such a sudden shake cannot provide a sufficient shake correction. In a picture taking, exposure is instructed by fully pressing a shutter release button. A sudden shake often occurs immediately after the operation of pressing the shutter release button due to a force applied thereto. Thus, if the shake correction and the exposure are started immediately after the instruction of the exposure, the reliability of the shake correction is considerably reduced.
In order to solve the above problem, for example, Japanese Unexamined Patent Publication No. 7-218970 discloses a shake correctable camera in which exposure is prohibited for a predetermined time which lasts until a sudden shake caused by the shutter release button pressing operation disappear after the instruction of exposure is given, in other words, exposure is started at a delayed timing after the instruction thereof.
Since the start of exposure is delayed by the predetermined time after the instruction thereof is given in the shake correctable camera disclosed in the above publication, it takes a long time until the exposure is completed after the shutter release button is operated. Particularly, if a sufficient delay time is provided to ensure the reliability of the shake correction, it gives a photographer an unnatural sense of shutter release. Further, even if the photographer performs a shutter release upon deciding that a good timing for shutter release has come, the exposure timing is delayed from the shutter release timing. Accordingly, the operability of the camera is considerably reduced.